A man described as a veteran Afghan pilot opened fire on NATO troops at an air base killing 9. No word on how many were wounded. The attacker was killed by security forces.

AP reports that since March of 2009, the coalition has documented "20 incidents where a member of the Afghan security forces or someone wearing a uniform used by them" attacked allied soldiers, killing a total of 36.

CNN Reports:

The NATO-led International Security Assistance Force in Afghanistan said an Afghan military pilot opened fire on international troops, sparking a "gunfight." The Taliban, however, claimed responsibility for the attack and said it had been working with the shooter for some time -- an assertion that NATO denied.

There also was confusion about the death toll. The NATO-led force initially said six service members were killed. It raised that toll to nine but backed away temporarily before saying again that the shooting killed nine people -- eight international service members and a civilian contractor.

The international force did disclose the nationalities of the eight service members and the civilian. An Afghan official said at least six U.S. troops were killed.

The shooting started at the Afghan national air force compound at North Kabul International Airport after an argument between an Afghan pilot and an international colleague, officials said. The NATO-led force said an Afghan military pilot opened fire on international trainers and a "gunfight" ensued.

"A 50-year-old man opened fire at armed U.S. military soldiers inside the airport after an argument between them turned serious," said Col. Baha Dur, chief of public relations for the Afghan National Army at Kabul military airport.

AP is also reporting that the Taliban has claimed responsibility, saying the pilot had been placed their for the purpose of killing troops. That claim has not been verified yet but it certainly is a possibility and the "argument" motive might be a cover-up.